So far, the search for extraterrestrial life has focused on planets at a distance from their star where liquid water is possible on the surface. But within our Solar System, most of the liquid water seems to be outside this zone. Moons around cold gas giants are heated beyond the melting point by tidal forces. The search area in other planetary systems therefore increases if we also consider moons. Researchers from SRON and RUG have now found a formula to calculate the presence and depth of subsurface oceans in these ‘exomoons.”
Source:
https://phys.org/news/2020-04-astronomers-formula-subsurface-oceans-exomoons.html